NER: Novel Applications Based on Attractive and Repulsive Electrostatic Forces in Nanoscale

Cornell University, Ithaca NY

Investigators

Abstract

Novel Applications Based on Attractive and Repulsive Electrostatic Forces in Nanoscale The focus of the proposed NER research is to establish an electrostatic interface between nanoelectronics and the biological molecular systems in the micron and nanometer scales. The main research actions include: 1. To seek concept demonstration for nanometer-to-micron-scale manipulation of the electrostatic attractive and repulsive forces through nonvolatile static charges controlled by CMOS/EEPROM (electrically erasable programmable read-only memory) devices. 2. To establish the spatial and energy resolution limits of the electrostatic forces between CMOS and biological systems 3. To establish the electrostatic interface between CMOS devices and the ambient electrolyte solution without chemical contamination in Si and dielectrics. 4. To formulate realistic goals and implementation methods in the follow-on NIRT effort for building molecular recognition and actuation capabilities derived from nanoscale CMOS technology, if the NER efforts give promising results. This proposed NER investigation is unique in the sense that the nonvolatile static charges in CMOS EEPROM devices are employed at the interface, and hence the interaction electrostatic forces can be both attractive and repulsive. For molecular recognition and actuation, availability of both attractive and repulsive forces at interface is crucial for high selectivity and sensitivity. Two technology demonstrations will be established in the NER effort to investigate the scale and resolution of the electrostatic attractive and repulsive forces derivable from the CMOS/EEPROM devices. The first one is the micron-scale electrostatic tweezers. For electrostatic tweezers actions of pickup and drop, an electrostatic repulsive force is needed. This can be accomplished by forces induced from nonvolatile static charges. The second one is the nano-scale molecular recognition from surface attractive and repulsive forces. Nanometer-scale molecular recognition by complementary nonvolatile static charges can be achieved in floating nanocrystal EEPROM structures. The peripheral source/drain structures have alternative dopant types to facilitate complementary static charge injection. The control gate is partially implemented by the ground-plane back gate to expose the nanocrystals for electrostatic interaction with the ambient. Preliminary concepts for the micron-scale [1,2] and nano-scale [3-6] nonvolatile static charge control have already been experimentally demonstrated in the PI's group. The micron-scale control currently offers much faster charge reconfiguration (in milliseconds) than the nanoscale one (achieved by floating Si and metal nanocrystals with pixel accessibility inversely proportional to resolution due to peripheral contact constraints). Present efforts by the PI in funded research programs will be discussed in view of the relations with this NER proposal. A small addition to the existing educational outreach program will be presented. Rationale has been made to fit the proposed effort to the one-year span of the NER program. If the concept demonstration is successful, a NIRT proposal will be composed next year based on the preliminary modeling and experimental results.